Friday, October 29, 2010

In the Soup

This is another one from my set of rain pictures -- a little chaotic around the edges, but I love the character of the bellhop at work, juggling rain, baggage, guests, the works.

I suppose I should talk a little bit about how I went about shooting the rain. If you want rain that kind of looks more drop-like (kind of like what our eyes see), shoot north of 1/320s. If you want long, cinematic streaks of rain, go lower -- probably south of 1/100s. I had a little physics debate in my head: Do fat raindrops fall heavier than small ones? Terminal velocity is going to be affected by things like the drag coefficient, the mass of the drop, and inversely proportion to the area. Would the drop being heavier have more of an influence than the larger area a fat drop would have? My meditation on the subject was cut short by Googling it on my phone, where I found this page, which tells you the terminal velocity of raindrops. Big and fat? About 30 feet/second. Tiny and drizzly? 6 1/2 feet/second. So, as rain gets fatter, you might end up needing more shutter speed to sort of freeze it as a drop -- but easier to get that long, flowing effect.

Ok, I'm probably boring you all by now, but at this point, I thought I was all set.

Well, not quite, and if you look at the picture above, you'll see why. Notice how the place where we see the rain most clearly is under the man's umbrella? I like it here, since it gives me the impression he's having a permanent rainy day -- but it's sort of the opposite of reality. What gives?

Well, basically, on some rainy days, you have flat, diffuse light everywhere. Pretty good for portraits of people, and bringing out some saturated, sunk colors -- but not so hot at making little drops of water stand out. The way I thought of it was that if the little drops of water get hit by light in any direction, light refracts off it equally from every way you look at it. It ends up being not standing out on the sensor. But give the light a direction, or drop the rain in front of a dark background, and the rain shows up again.

That's my theory at least, and it was certainly born out by all the rain I saw last weekend.

If you are stuck in flat, diffuse light, what should you do with your rain? Well, I think most of our brains are pretty good at accepting the fact that there's more rain near umbrellas. It's aphysical, but there's some weird logic to it our brain accepts. You can also look for dark surfaces to set your rain against (plenty of asphalt in the city), or wait for the errant ray of sunlight (or city lights, if it's night) to pop out. The other option would be flash -- of course, lots of electricity flying around there, so you really would have to wrap everything up if you wanted to end up not frying your flash (or at least discharging the batteries). That would probably put me outside my limit for carting around gear and remaining nimble, but to each their own.